龚建明, 廖晶, 尹维翰, 张莉, 何拥军, 孙治雷, 杨传胜, 王建强, 黄威, 孟明, 成海燕. 北印度洋马克兰增生楔天然气水合物的成藏模式[J]. 海洋地质与第四纪地质, 2018, 38(2): 148-155. DOI: 10.16562/j.cnki.0256-1492.2018.02.015
引用本文: 龚建明, 廖晶, 尹维翰, 张莉, 何拥军, 孙治雷, 杨传胜, 王建强, 黄威, 孟明, 成海燕. 北印度洋马克兰增生楔天然气水合物的成藏模式[J]. 海洋地质与第四纪地质, 2018, 38(2): 148-155. DOI: 10.16562/j.cnki.0256-1492.2018.02.015
GONG Jianming, LIAO Jing, YIN Weihan, ZHANG Li, HE Yongjun, SUN Zhilei, YANG Chuansheng, WANG Jianqiang, HUANG Wei, MENG Ming, CHENG Haiyan. Gas hydrate accumulation models of Makran accretionary wedge, northern Indian Ocean[J]. Marine Geology & Quaternary Geology, 2018, 38(2): 148-155. DOI: 10.16562/j.cnki.0256-1492.2018.02.015
Citation: GONG Jianming, LIAO Jing, YIN Weihan, ZHANG Li, HE Yongjun, SUN Zhilei, YANG Chuansheng, WANG Jianqiang, HUANG Wei, MENG Ming, CHENG Haiyan. Gas hydrate accumulation models of Makran accretionary wedge, northern Indian Ocean[J]. Marine Geology & Quaternary Geology, 2018, 38(2): 148-155. DOI: 10.16562/j.cnki.0256-1492.2018.02.015

北印度洋马克兰增生楔天然气水合物的成藏模式

Gas hydrate accumulation models of Makran accretionary wedge, northern Indian Ocean

  • 摘要: 印度洋北部马克兰增生楔是阿拉伯板块低角度俯冲到欧亚板块之下形成的,平面上具有北部沉积速率高,沉积厚度大,南部逆冲断裂和紧闭褶皱发育,且构造活动具有北部拉张与南部挤压的特征;纵向上具有深部断裂活动强与浅部构造相对稳定的特点。这种复杂的活动大陆边缘具有世界上超低的俯冲角度和良好的水合物成藏条件,因此,平面上水合物矿藏类型多样,其中,下陆坡和增生楔前缘主要受叠瓦状逆冲断层的控制而形成“阶梯式增生楔型”水合物藏,而中陆坡和上陆坡主要受沉积厚度和北部拉张的控制作用而形成“底辟型”和“泥火山型”水合物藏。纵向上马克兰增生楔水合物矿藏具有“二层楼结构”的成藏模式,即深部主要受逆冲断层的控制,而浅部主要受正断层的控制。上述成藏模式可能与阿拉伯板块低角度俯冲有关。

     

    Abstract: The Makran accretionary wedge, located in the northern Indian Ocean, is resulted from the subduction of the Arabian plate under the Eurasian plate at a low dip angle. In the northern part of the accretionary wedge, sedimentation rate is high and sediments are thick, while in the southern part, thrust faults and tight anticlines dominate. The tectonics is characterized by extension in north and compression in south. In vertical direction, however, faulting activities are strong in the deep and weak in the shallow part. It is a complicated active continental margin characterized by an ultralow angle subduction plate in the world and thus has good conditions for hydrate accumulation. So far, different types of hydrate accumulations have been found. The hydrate accumulation of multi-stepped accretionary wedges mainly occur in the Lower-Slope and Deformation Front under the control of imbricate thrust faults, while the hydrate accumulation of mud diapirs and mud volcanoes types mainly occur in the Mid-Slope and Upper-Slope, which are jointly controlled by sediment thickness and the tectonic tension in the north. Vertically, the hydrate accumulations are characterized by so called "Double floor structure". It means that deep accumulations are mainly controlled by thrust faults, while shallow ones are mainly under the control of normal faults. The above-mentioned hydrate accumulation models may owe their origin to the low angle subduction of the Arabian Plate towards the Eurasian Plate.

     

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